1. Field
The present disclosure relates to a toner for developing an electrostatic charge image, a method of preparing the same, a device for supplying the same, and an apparatus and a method of forming the image using the same.
2. Description of the Related Art
A method of preparing toner particles suitable for use in an electrophotographic process and an electrostatic image recording process may be largely classified into a pulverization method and a polymerization method.
Conventionally, toners used for image-forming apparatuses are mainly prepared through the pulverization method. Since the precise control of toner particle size, narrow particle size distribution, and toner shape is difficult in terms of the pulverization method, it is difficult to independently design each important property required for a toner such as charging, fixation, fluidity, or storage ability.
Therefore, in order to cope with the recent requirements of high quality, high reliability, and high productivity for a multi-functional digital color printer and other color printers, a polymerized toner has attracted interest because control of particle diameter and shape is easy and performance of a complex manufacturing process such as classification is not necessary. When a toner is manufactured by using the polymerization method, a polymerized toner having a desired particle size and particle size distribution may be obtained without pulverizing or classification. Since a toner manufactured by using the polymerization method has a smaller particle diameter, narrower particle size distribution, better circularity, and easier control of morphology than one manufactured by the pulverization method, the polymerized toner has advantages such as high charging and transfer efficiency, high resolution through good dot reproducibility and line reproducibility, wide color gamut, low toner consumption, and high image quality. In typical polymerized toners, copolymer resins of styrene and an acrylate were mainly used as a binder resin, but improvements in transparency and low-temperature fixation of the binder resin are required according to a recent increase in application areas of color toners.
To obtain the foregoing properties, toner particles were suggested in U.S. Pat. No. 6,617,091. The suggested toner particles has a resin layer (shell) formed on a surface of a colored particle (core particle) containing a resin and a colorant in order to provide a polymerized toner which has a less amount of colorant on the surface of the particle and does not generate changes in image concentration, fogging, and color changes of color image caused by changes in chargeability and developability even if the toner particles are used to form images under highly humid conditions over an extended period of time. This method may improve charge uniformity between colors to some extent by suppressing exposure of pigments to the surface of the toner particles. However, for example, when a lot of wax is contained, heat storage ability and fluidity of the toner may be reduced because of a plasticizing effect caused by some degree of miscibility between a low molecular weight portion of the wax and the resin. Also, for low-temperature fixation, a method is being suggested, in which the surface of a binder resin having a low glass transition temperature (Tg) is encapsulated with a binder resin having a relatively high Tg. However, this method may achieve the objective of the low-temperature fixation, but heat storage ability and gloss are not sufficient.